Spark control mechanism



Aug. 30, 1938. J. 5. JENNINGS, JR 2,128,363

- SPARK CONTROL MECHANISM Filed Aug. 8, 1936 2 Sheets-Sheet l we, WYW

I ATTORNEY Aug. 30, 1938.

J. 5. JENNINGS, JR

SPARK CONTROL MECHANISM Filed Aug. 8, 1936 2 SheetsShect 2 I INVENTOR Jkzn zs 6: 72272717 75, J 7:

BY MIA, Y

ATTORNEY Patented Aug. 30, 1938 d I I 2,128,363

UNITEDVSTATES PATENT OFFICE SPARK CONTROL 'ME OHANISM Jarvis S. Jennings, Jr., Detroit, Mich assignor to Monarch Governor Company, Detroit, Mich., a corporation of Michigan Application August 8, 1936, Serial No. 94,989 9 Claims. (01. 123-117) This invention relates to internal combustion Accordingly it is one of the objects of the engines and more particularly to vacuum conpresent invention to provide a novel spark controlled spark advance devices used-with such trol device which effects a proper spark occurengines. rence for all conditions of engine operation and In the operation of an internal combustion enresponds to the changes inboth the speed and 5 gine having a vacuum or suction type governor the torque developed. installed in the intake passage between the car- Another object of the invention isto provide a buretor throttle valve and the intake manifold novel spark control'device having a movable there are found to exist between the atmospheric pressure responsive valve controlling the passages 10 end and the engine end of the intake passage communicating withadiaphragm casing in'which 10 three pressure zones, pressures in each of said is housed a diaphragm responding to the changes zones varying in accordance with changes in op'- in engine operating conditions irrespective of eration conditions of the engine. There is a whether such changes produce any material difpressure zone, substantially atmospheric, at the ference between the pressures above and below upstream side of the carburetor valve; a pressure the governor valve. 16 zone between the carburetor and governor valves; A still further object of the invention-is to and a pressure zone downstream ofthe governprovide a novel spark control device having a ing valve, 1. e., at the manifold or engine side of piston valve which, when the engine is idling, the intake passage. Pressures in these three will be brought'into position to permit retarda- 0 zones, and particularly in the last two zones, diftion of the spark, said valve being controlled at 20 fer in accordance with the conditions of engine this time by atmospheric or near atmospheric operation, and particularly with the speed and pr s r in h z n p r m r e arthe torque developed. buretor valve.

The change of respective pressures i aid A further object of the invention isto provide zones has been utilized in many structures in ora novel spark control device having a piston Valve 25 der to effect the desired spark control. However, which responds to predetermined Pressure difliculties have been encountered in providing a changes in t e intake passage when the cardependable and a. quickly responsive spark conburetor throttle, is moved from a partially closed trol means, which difiiculties are due chiefly to Position to i n p s t th y efieeting' the fact that the pressure difierence between the a P arly large spark retard for a very slow two particular zones which are usually chosen to engine Operation When the engine is idling for actuate said means does not vary or behave in a 10118 Period of timea desired way or does not reach a sumcient alue. A further object Of the invention is to I have fou d that a dependable and quickly provide a novel spark control device in which responsive spark -control of an engine cannot be the Pressure responsive Valve is adapted to be 35 adequately obtained by means of a, mechanism subjected at both of its efiective sides under all operated by a piston alve responsive merely to engine Operation conditions, except to the the pressures above and below the governor valve, pressure existing Same Pressure Zone, inasmuch as in many instances the conditions of thereby eventing hesitation hunting of the 40 engine operation change so asto require corre- Valve under said Cenditions and permitting firm 40 sponding change in Spark occurrence, whereas holding of the valve in a desired operative posisuch changes are not always accompanied by any material change in the diiference of respective A still further Object o t e nvent o s to P pressures atopposite sides of the governor valve. Vide a device of the abQVe Character Which is Moreover, in many instances requiring response simple in construction and does not require close 45 of the piston valve, said pressure diff r i calibration of its springs or of other means emvery slight and a very close calibration of the p spring or other means employed must be depend- Other objects of this invention will appear in ed upon to assure sufiicient response of the pisthe following description and appended claims,

ton valve under such conditions. Consequently, reference being had to the accompanying draw- 50 such devices have the disadvantages either of reings forming a part of this specification wherein quiring close calibrations and adjustments or of like reference characters designate corresponding not always responding to changes in engine operparts in the several views. ation conditions. Hence, they accomplish at best In said drawings: 7

only a partial sparkcontrol. Fig. 1 is a perspective view partly broken away 55 showing the carburetor and the governor as the same are operatively connected in the engine intake passage.

Fig. 2 is a vertical sectional view of a spark control device embodying my invention, showing the relative positions of parts for the following operation conditions: full carburetor throttle with a full governor valve opening (high torque, low speed) full carburetor throttle with the governor valve partly closed (governing condition at increasing speed) both the throttle and the governor valve partially closed. For each of said conditions the positions of both the throttle and the governor valve are indicated by similar types of lines.

Fig. 3 is a view similar in part to that of Fig. 2, showing the relative positions of parts under idling operation condition of the engine.

Before explaining in detail the present invention it is to be understood that the invention is not limited in its application to the details of construction and arrangement of parts illustrated in the accompanying drawings, since the invention is capable of other embodiments and of being practiced or carried out in various ways. Also it is to be understood that the phraseology or terminology employed herein is for the purpose of description and not of limitation, and it is not intended to limit the invention claimed herein beyond the requirements of the prior art.

In the drawings there is illustrated a part of the intake passage of an internal combustion engine, namely, the portion thereof including the carburetor and the governor valves, as well as the portions immediately adjacent thereto, showing my novel spark control device in operative arrangement with respect to said passage. There is also shown the casing of a diaphragm adapted to change the position of an engine distributor, or other spark current controlling means. In the present embodiment, shown by way of example, the diaphragm is so arranged that when subjected to atmospheric pressure it holds the spark retarded. On the other hand, when it is subjected to the action of the vacuum developed in a given zone in the engine intake passage, said diaphragm operates against the action of a special spring to advance the spark in accordance with the degree of vacuum existingin said zone at the moment.

Referring more particularly to the figures, there is shown a carburetor casing I0 provided with suitable flanges I I adapted to be secured to flanges I2 of the governor body I3. Within the carburetor casing I0 there is operatively arranged in the intake passage therethrough a throttle valve I4 of the butterfly type adapted to be operated in a manner well known in the art. Within the governer body or casing I3 there is operatively arranged in the intake passage leading to the engine intake manifold a governor valve I5 of the butterfly type adapted to restrict the passage in accordance with the set requirements of the governor. The reference letter A indicates the pressure zone in the intake passage above or at the upstream side of the carburetor throttle; B indicates the pressure zone between the carburetor valve I4 and the governor valve i 5; and C indicates the pressure zone in the intake passage below or at the downstream or manifold side of the governor valve I5.

The spark control device comprises generally a piston valve It slidable in a cylinder I'I provided within the governor casing I3, and a diaphragm greases mechanism i8 operating in the spark controlling means.

The diaphragm mechanism I8 comprises a casing consisting of two flanged pieces I9 and I911 between which is held a thin corrugated diaphragm 20 operatively connected by means of a piece 2! and a rod 22 to the distributor 23 of a conventional design. The space 24 of said casing is hermetically sealed and is connected by means of a diaphragm conduit 25 with the cylinder I'I, while the space 24a. is not sealed and communicates with the atmosphere. If a connection is established between said diaphragm conduit 25 and the pressure zone C, the action of vacuum transmitted to the space 25 operates to move said diaphragm against the resistance of the spring 26 toward the conduit 25, which movement of the diaphragm is transmitted by the rod 22 to the distributor 23 thereby moving the same into a position eiTecting an advance of the spark in proportion to the degree of vacuum acting upon said diaphragm. As the degree of the vacuum in the space 26 decreases, the spring 26 becomes efiective to move the diaphragm away from said diaphragm conduit 25, thereby moving the dis tributor in a position effecting a correspondingly smaller spark advance. When a connection between the conduit 25 and the atmosphere is effected, the air pressure at both sides of the diaphragm 20 becomes balanced, and the spring 26 moves the diaphragm 29 into a position eiiecting a particularly large spark retard.

Connected to the casing I0 is a pipe or a conduit 27 which communicates with the intake passage through ports 28 and 29 located, respectively, just above and below the place at which the edge of the carburetor valve I4 is about to engage the walls of the casing II! when the engine is set for idling. The ,opposite end of said conduit 21 communicates with a port 38 leading into the upper end of said cylinder Il. Atmospheric conduit 3i connects the cylinder IT with the atmosphere. In the present embodiment its inner end 32 communicates with the cylinder I? and the outer terminal 320. thereof is connected to the atmospheric space 33a of the governor casing which space is provided with atmospheric outlets 34 and 35 between which there is interposed suitable packing 36, protecting the interior of said casing from dust and dirt and preventing them from getting into the cylinder II through said conduit 3I.

The governor casing 33 which is offset to one side of the body I3 houses the mechanism controlling the governor valve I5. Said mechanism consists of a balanced spring 3! adjustable by means of an adjustment disk 38, which spring bears upon the piston 39 slidably fitted within said casing and provided with a piston rod 40 carrying a cam M cooperating with a roller 42 carried by the crank arm 43 secured to the governor valve shaft I50, suitably journalled in the governor body I3 to which shaft the governor valve is fastened. Space 3373 communicates with the intake passage of the engine below the governor by means of a passage 330 leading from said space to the portion I3, as is clearly indicated in Fig. 1. The space 33a is provided with atmospheric outlets, as mentioned. With the increase or decrease of engine speed, the vacuum below the governor valve increases or decreases, causing corresponding movements of the piston 39 against said spring 31, thus moving the piston rod 40 and the cam ll. The roller 42 following the outline of the cam actuates the arm 43 and the governor proach atmospheric pressure.

valve shaft I511, thereby closing or opening the governor valve 15.

A conduit 44 arranged substantially parallel to the cylinder I'I provides through the medium of ports 45 and 46 a communication between the zone B and the lower end of the cylinder l1, while the conduit 41 connects the middle portion of the cylinder ll with the zone C through the medium of ports 48 and 49 respectively.

In the present embodiment of the invention the piston valve is in the form of an elongated cylindrical piece slidably fitted within the cylinder I1, and provided with an extension 50 and annular recesses 5| and 52. A spring 53 is provided in the cylinder I! under the piston valve l6 and, unless compressed by the pressure upon the piston valve I 6, said spring holds the piston valve in the extended position shown in Fig. 2, which position is determined by the length of the extension 50 which serves as a stop of the piston valve I 6 in the upward movement thereof. The length of the cylinder and of the valve I 6, as well as the respective location of ports in said cylinder and recesses in said valve, is such that the end 32 of the atmospheric conduit 3| is always included within the recess 5| of the piston valve I6, while the port 49 of the conduit 47 is always included within the recess 52, conduits 44 and 21 communicating with cylinder [1 above and belowv the piston at all times. Port 54 of the diaphragm conduit 25 is included, depending upon the position of the piston valve l 6, either in the recess 5| or the recess 52. When said port 54 is included in the recess 52 (see Fig. 2) the atmospheric conduit 3| has no communication with the diaphragm conduit 25, said diaphragm conduit being connected by means of the recess 52 and conduit 41 with the zone C. 0n the other hand, when the port 54 is included in the recess-5| (see Fig. 3), communication between zone C and the diaphragm conduit 25 is interrupted, and communication between said diaphragm conduit and the atmospheric conduit is established through the medium of recess 5|.

When the engine operation conditions are such that spark advance is desired, the means hereinbefore described cooperate to connect the diaphragm vacuum space 24 with the pressure zone C where the degree of vacuum is the greatest, and the spark is advanced because of the movement of the diaphragm 20 in proportion to the degree of vacuum in said zone C. When the engine is operating at the wide open throttle and maximum torque, which may be a condition arising from acceleration or hill climbing or the like,

the engine should operate with a substantially retarded spark. Operation of the present spark control device effecting the proper spark occurrence for such operation conditions is illustrated in Fig. 2. Under such operation conditions both the carburetor throttle valve and the governor valve are in the positions indicated by the numerals .55 and 56, respectively. The pressures in the zones A, B and C are under such conditions nearly equal and in magnitude ap- The substantially atmospheric pressure is transmitted through the conduit 21 into the cylinder space above the piston valve l6, and through the conduit 44 into the space under the piston valve l6. Consequently, as far as fluid pressure is concerned, the'piston valve I6 is in a substantially balanced condition, which is to say that there is no re sultant force tending to move said piston valve.

Therefore, the spring 34 can firmly hold the piston valve IS in its extended position, thereby efiecting communication of the vacuum space 24 of the diaphragm casing with the pressure zone C wherein a. nearly atmospheric pressure exists at the moment, as explained. Said communication is effected through the port 48, conduit 41, port 49, recess 52, port 54 and conduit 25. Subjected to a nearly atmospheric pressure, the diaphragm 20 aided by the spring 26 moves down and pushing on the rod 22 sets the distributor 23 into a position eifecting a substantially retarded spark, which is required for the proper operation of the engine under such conditions.

With the carburetor throttle wide open as described, should the torque required begin to decrease, the engine speed will increase proportionally and may become objectionably high. Such.

conditions may arise during acceleration in lower gears or in speeding in high gear. Under such conditions the governor valve moves toward the position shown at 51 keeping the speed of the engine at the predetermined maximum. As a result of such position of the governor valve l5, a substantially atmospheric pressure will continue to exist in both the zone A and the zone B, while a certain degree of vacuum is created in the zone- C. Atmospheric pressure acting above and below the piston valve l6, as before, the valve .will be still firmly held in its extended position under the full force of the spring 53, while because of the space 24 communicating with the zone C of increased vacuum, the diaphragm 20 responds to the vacuum in said zone C and advances the spark in proportion to the degree of vacuum created in said zone, that is to say in proportion to the closing of the governor valve and, consequently, in proportion to the increasing speed of the engine.

When the carburetor throttle valve I4 is in its partially closed position as at 58, the governor valve will ordinarily assumeapproximately the position indicated by the numeral 59, which position is substantially the same as that of the carburetor throttle valve l4. Under these conditions there will be atmospheric pressure in the zone A and a partial vacuum in the zones B and C. It will be noticed from an examination of the position 58 of the carburetor throttle valve that the port 28 of the conduit 21 is located in the zone B rather than in the zone A, and consequently, the piston valve l6 will again be subjected to the equal or nearly equal pressures on both of its effective sides. As a consequence the fluid pressure does not efiect the operative position of the piston valve l6, and the spring 53 holds the piston valve in its extended position, causing the diaphragm conduit 25 to maintain communication between the zone C and the space 24 of the diaphragm casing. This causes the diaphragm 20 to advance the spark in proportion to tially opened position into the practically closed position for idling. It will be appreciated that under such conditions there will be practically no change in the difference of pressures in the zones B and C and, consequently, if the piston valve is responsive only to the difference of pressures in the zones just above and below the governor valve, as heretofore it will not respond operatively when the engine is set for idling.

The operation of the spark control device when the engine is set for idling is illustrated in Fig. 3. It will be appreciated that under idling operation both the throttle l4 and the governor valve l5 are practically closed, and there is a high vacuum created in the pressure zones B and C. As can be noted from an examination of Fig. 3, the carburetor throttle valve I4 is nearly set down upon the walls of the casing Ill with its upper edge located between ports 28 and 29. Therefore, the port 28 becomes located in the pressure zone A and the port 29 in the pressure zone B. The flow of air from the zone A through port 28 reduces the degree of vacuum acting upon the piston valve It, or in other words, causes a higher pressure to act upon the top of said piston valve. At the same time the increased vacuum in the pressure zone B is caused to act upon the lower side of the piston valve l6. As a result, the spring 53 is compressed, and the piston valve 16 is brought into the position shown in Fig. 3. In this position of the piston valve the vacuum space 24 of the diaphragm casing communicates with the atmosphere through the conduit 25, port 56, recess 5|, port 32, atmospheric conduit 3|, port 3241, atmospheric side 33a of the governor casing and openings 34 and 35. In consequence thereof, the diaphragm 20 is moved into the position shown in Fig. 3, causing a retarded spark, which is required for a proper operation of the engine under idling conditions. Thus, when the throttle valve i4 is moved from a position of partial opening into the position for engine idling, the piston valve l6 operativelyresponds thereto and sets the spark in a properly retarded position. It will be understood that with the carburetor valve I 4 set in the position shown in Fig. 3, the pressure in the conduit 21 will approach atmospheric, since the effect of port 29 at this time is minimized. In some instances to suit particular engine requirements the passage or port 29 may be dispensed with so that under engine idling conditions substantially atmospheric pressure will exist in the conduit 27.

I claim:

1. In a spark control device for an engine provided with an intake passage having a carburetor throttle valve and a governor valve therein, spark control means normally responsive to the pressure in' the intake passage at the engine side of said governor valve, and a control valve responsive entirely to pressures existing at the upstream side of said governor valve, said control valve being efiective at a predetermined time to subject said spark control means entirely to the action of the atmospheric pressure.

2. In a spark control device for an engine provided with an intake passage having a carburetor throttle valve and a governor valve therein, spark control means normally responsive to the difference of pressures in the atmosphere andin the intake passage at the engine side of said governor valve, and a control valve responsive entirely to pressures existing at the upstream side of said governor valve, said control valve being effective in engine operation conditions requiring particularly large spark retard to subject said spark control means entirely to the action of the atmospheric pressure.

3. In an internal combustion engine provided with an intake passage having a carburetor throttle valve and a governor valve therein, the

combination with a spark control device having a diaphragm normally responsive to the pressure in the intake passage at the engine side of said governor valve, of a control valveresponsive entirely to pressures existing at the upstream side of said governor valve and effective at a predetermined time to cut off responsiveness of said diaphragm to pressure in the intake passage and cause atmospheric pressure to act on said diaphragm.

4. In a spark control device for an engine pro vided with an intake passage having a carburetor valve and a governor valve therein, a spark controlling diaphragm, a cylinder, a recessed piston slidably fitted in said cylinder, a conduit connecting said cylinder at one side of the piston valve to the pressure zone between the carburetor and governor valves, a second conduit connecting said cylinder at the opposite side of the piston valve to the pressure zone upstream from the carburetor valve when the latter is substantially closed, a diaphragm vacuum conduit connecting said diaphragm with said cylinder, a vacuum conduit connecting said cylinder with the pressure zone at the engine side of the governor valve, and an atmospheric conduit connecting said cylinder with the atmosphere, said piston valve being movable when the carburetor valve is substantially atmosphere through a path omitting said intake passage, a diaphragm conduit connecting said cylinder with the diaphragm, and a vacuum conduit connecting said cylinder with the intake passage at the engine side of the governor valve, said piston normally closing the atmospheric conduit and connecting said diaphragm conduit and said vacuum conduit, and effective in idling condition of the engine to close said vacuum conduit and to connect said atmospheric conduit and said diaphragm conduit.

6. In a spark control device for an engine provided with an intake passage having a carburetor valve and a governor provided with a governor valve in said passage and a casing offset therefrom and having a space subject to atmospheric pressure, a spark controlling diaphragm, a cylinder, a two-recess piston slidably fitted within said cylinder and responsive entirely to pressures existing at the upstream side of said governor valve, an atmospheric conduit connecting said cylinder with the atmosphere, a diaphragm conduit connecting said cylinder with the diaphragm, and a vacuum conduit connecting said cylinder with the intake passage at the engine side of the governor valve, said piston normally closing the atmospheric conduit and connecting said diaphragm conduit and said vacuum conduit, and eiiective in idling condition of the engine to close said vacuum conduit and to connect said atmospheric conduit and said diaphragm conduit, said atmospheric conduit being connected to said space within the governor casing.

7. In an internal combustion engine provided with an intake passage having a carburetor throttle valve and a governor valve therein, the combination with a spark control device having a diaphragm open at one side at all times to atmosphere, of a control valve responsive entirely to pressures existing at the upstream side of said governor valve, said control valve being eflective at a predetermined time to subject the other side of said diaphragm to the action of the atmospheric pressure.

8. In an internal combustion engine provided with an intake passage having a carburetor throtto the action of substantially atmospheric pressure.

9. In a spark control device for an engine provided with an intake passage having a carburetor valve and a governor valve therein, a spark controlling diaphragm normally operatively connected and responsive to pressure in the intake passage at the engine side of the governor valve, the other side of said diaphragm being open to atmosphere at all times, a recessed piston efl'ective in engine operation conditions requiring aparticularly large spark retard to interrupt the communication between the intake passage of the engine and said diaphragm and to establish a communication between said diaphragm and the atmosphere through a path omitting said intake passage, whereby said diaphragm becomes subjected at both of its sides to the action of atmospheric pressure.

JARVIS S. JENNINGS, JR. 20 

